ventilation question

[liquidkush]

I'm building a grow room in a closet with the dimensions of ( H=4FT W=3FT L=2FT). I'm getting a 400w HPS. What I want to know is how much plants could I fit in this area? and how should I go about ventilation. the area I live in never goes below 70degrees summer time . I live in a high place so the air is always circulating through the main room (knocking over pics etc..). The closet have two swivel doors in front and I have the sightest idea how to vent it, any help will be appreciated....One more thing do I need to vent the area for the veg compartment(I was thinking on using a large rubbermaid green container) ? Thanks for the help

[liquidkush]

Here go some pics